Automatic sheet feeder

ABSTRACT

An automatic sheet separator and feeder in which an end of the uppermost sheet in a stack of sheets supported on a bottom wall of a tray is lifted over an abutment wall of the tray into contact with a driven member and a shoe is moved to position its toe over the stack of sheets to separate the lifted sheet from the remaining stack of sheets and its sole engaged with a driven member to place the lifted end of the sheet in driving engagement with the driven member to feed the sheet from the stack of sheets.

ilnited States Patent Inventor Donald B. Lucius Bloomington, Minn. Appl.No. 869,125 Filed Oct. 24, 1969 Patented Dec. 7, 1971 Assignee MinnesotaMining and Manufacturing Company St. Paul, Minn.

AUTOMATIC SHEET FEEDER 6 Claims, 7 Drawing Figs.

10.5. C1 27 M33 lint. Cl 1365b 3/20 Field 01 Search 271/26, 20, 30, 33

References Cited Primary Examiner.loseph Wegbreit Attorney-Kinney,Alexander, Sell, Ste1dt& Delahunt ABSTRACT: An automatic sheet separatorand feeder in which an end of the uppermost sheet in a stack of sheetssupported on a bottom wall of a tray is lifted over an abutment wall ofthe tray into contact with a driven member and a shoe is moved toposition its toe over the stack of sheets to separate the lifted sheetfrom the remaining stack of sheets and its sole engaged with a drivenmember to place the lifted end of the sheet in driving engagement withthe driven member to feed the sheet from the stack of sheets.

PATENTEDDEC Hen 3625507 SHEET 1 [IF 2 I INVENTOR.

DONALD E. Luc/us BY/f 41 M M WmQwQ/A AT TORNE Y5 AUTOMATIC SHEET FEEDERThe present invention relates to an automatic sheet separator and feederfor feeding sheets from a stack thereof over an abutment memberseriatim.

The prior art sheet feeders have generally required the use of sheetshaving uniform consistency to provide the feeding of a single sheet at atime. While this has been satisfactory in some uses, it has not beensatisfactory for automatically feeding original documents to areproducing machine since it is often desired to be able toautomatically reproduce original documents of varying size andconsistency with a single reproducing machine. Recently it has beenfound that original documents of varying consistency may be lifted froma stack by contacting the uppermost sheet with a small area ofpressure-sensitive adhesive tapeand then lifting the tape and sheet fromthe stack. To complete the feeding of the sheet some means must beprovided for removing the sheet from the pressure-sensitive adhesivetape. In the prior art this has generally been accomplished by the useof a stripper arm or plate pushing the sheet from the adhesive tape asillustrated by U.S. Pat. No. 2,919,129. However, such devices aredisadvantageous in that they are generally slow in feeding a pluralityof sheets and, more seriously, the sheet is not positively engaged as itis removed from the adhesive tape and the sheet may not be appropriatelyfed after removal from the tape. Furthermore, when the uppermost sheetis lifted from the stack, a second sheet may be attracted to it bystatic electricity and may be lifted with it, particularly when thesheets in a stack are light, thin and similar.

It is an advantage of the present invention to provide a fast automaticsheet feeder in which the uppermost sheet is lifted from a stack ofsheets and positively engaged and fed as it is removed from the meansfor lifting it. It is a further advantage of the present invention toprovide an automatic sheet feeder in which the uppermost sheet isseparated from the remaining sheets in the stack as it is lifted fromthe stack. It is a still further advantage of the present invention toprovide an automatic sheet feeder in which the uppermost sheet in astack of sheets is lifted from the stack on a piece of adhesive tape andpositively engaged and peeled from the adhesive tape and fed along thedesired path as the lifted sheet is separated from the remaining sheetsin the stack.

The present invention has the advantages desired of an au tomatic sheetseparator and feeder and comprises support means including a bottom wallfor supporting a stack of sheets and an abutment member over which it isdesired to feed sheets seriatim, sheet-lifting means for lifting the endof the uppermost sheet in the stack above the abutment member, drivenmeans extending over the support means abutment member to contact thelifted end of the uppermost sheet, and shoe means positioned below thedriven means and having a toe to extend over the stack of sheets forseparating the lifted sheet from the stack and a sole engageable withthe driven means to place the lifted end of the uppermost sheet indriving engagement with the driven means.

The novel features and advantages of the present invention will becomeapparent after reading the following description which refers to theaccompanying drawings wherein:

FIG. 1 is a top perspective view of an automatic feeder made inaccordance with the present invention and assembled in a cabinet, afragment of which is shown;

FIGS. 2, 3, and 4 are schematic vertical sectional views il' lustratingoperation of the automatic sheet feeder through successive positions;

FIG. 5 is a fragmentary vertical sectional view taken generally alongline 55 of FIG. I with the cabinet sectioned;

FIG. 6 is a fragmentary vertical sectional view taken generally alongline 6-6 of FIG. I with the cabinet sectioned; and

FIG. 7 is a fragmentary top view of the feeder with the cabinet removed.

An automatic sheet feeder made in accordance with the present inventionand generally designated 10 is illustrated in the accompanying drawings.It comprises a tray 12 having a bottom wall 14 and an end or abutmentwall 16, a tape head 18, a sheet feeding belt 20 and a shoe 22.

The bottom wall 14 of the tray 12 is a rectangular planar plate that ispivotably supported by a shaft 24 that extends parallel to the abutmentwall 16 of the tray 12 near the end of the bottom wall I4 farthestremoved from the abutment wall 16. The shaft 24 is supported at its endsby a pair of stationary feeder support castings 25 and 27. The bottomwall 14 provides support for a stack of sheets 26 such as sheets of copypaper or original documents which are to be fed to a reproducing machinefrom the stack. A compression spring 28 positioned adjacent the abutmentwall 16 and spaced to one side of the center of the width of the bottomwall 14 supports the free end of the bottom wall 14 and biases itupward. The abutment wall 16 is planar and extends generallyperpendicular to the bottom wall I4. The bottom wall 14 and the abutmentwall 16 are normally positioned at an angle to the horizontal so thatgravity will aid in moving the stack of sheets along the bottom wall 14against the abutment wall 16. Along the upper edge of the abutment wall16 a generally horizontal plateau 30 connects the abutment wall 16 to adownwardly inclined sheet-feeding wall 32 onto which it is desired tofeed the sheets 26 from the stack on the bottom wall 14 seriatim.

The tape head 18 comprises a length of pressure-sensitive adhesive tape34 extending between a pair of spools in a housing 36 over an exposedsurface of a support finger, the length of tape being advanced acrossthe finger stepwise as the tape head is moved through successive feedingmovements such as disclosed in US. Pat. No. 2,9l9,l29 issued to R. L.Sjostrom. The tape head 18 is supported at the end of an elongated arm38 with the exposed portion of the pressure-sensitive adhesive tape 34supported above the bottom wall 14 of the tray 12 generally centrally ofthe width thereof near the abutment wall 16. The arm 38 is formed as apart of the tape head housing 36 extends into the feeder cabinet 11where it is formed with a support and driving block 40. A curved link 42is rotatably supported at one end on a normally stationary pin 43 andits free end is rotatably supported on a pin.44 secured to the tape headsupport and driving block 40. A straight link 46 formed with a pair ofparallel arms one to each side of the curved link 42 and connected bycylindrical sleeves is rotatable about a shaft 47 secured to the supportand driving block 40. The shaft 47 extends through one of thecylindrical sleeves of the straight link which is also supported on ashaft 48 passing through the other of its cylindrical sleeves andsecured to the stationary support casting 25. The curved link 42, thestraight link 46, the tape head support and driving block 40, and thestationary support casting 25 form a four-bar linkage to providemovement of a tape head 18 as will be hereinafter described.

The driving of the tape head four-bar linkage is provided by a crank arm50 that is rotatable about one end on a shaft 51 extending from thesupport and driving block 40 and at its opposite end about a pin 53extending off center from a driving disk 52. The driving disk 52 isformed in two sections which are rigidly secured together by the pin 53with the crank arm 50 free to rotate about the pin 53 between the twosections. The portion of the driving disk 52 farthest removed from thefeeder tray 12 is supported centrally on a driven shaft that extendsthrough the stationary support casting 25 to a one-way spring clutch 57carried on a driving shaft 55 that is driven by a pulley 59. The pulley59 is continuously driven by a motor (not shown) through a belt 60 andit drives the shaft 55. A plunger arm 62 of a solenoid 61 normallyengages the clutch 57 to prevent its rotation and thereby to preventrotation of the driving disk 52. Upon actuation, the solenoid 61retracts the plunger arm 62 to permit the clutch 57 and thereby thedriving disk 52 to rotate with the pulley 59 in a counterclockwisedirection as viewed in FIG. 5.

The shoe 22 comprises a thin link of a relatively nonfrictional materialsuch as nylon. It is secured at one end by an adjustment link 65 to arotatably supported hexagonal shaft 66 that extends parallel to theabutment wall 16 of the tray 12 adjacent the lower end thereof. The shoe22 extends from the hexagonal shaft 66 on the opposite side of theabutment wall 16 from the bottom wall 14 of the tray 12. It extendsupward nearly to the upper edge of the abutment wall 16 and then throughan aperture 68 formed in the abutment wall 16 and the horizontal plateau30 to normally lie over the edge of the bottom wall 14 of the tray 12.Along its uppermost portion the shoe 22 is formed with a smooth curvedsurface herein designated the sole 70 of the shoe and over the bottomwall 14 it tenninates in a generally pointed projection hereindesignated the toe 72 of the shoe. The shoe 22 is positioned generallycentrally of the width of the bottom wall 14 of the tray 12 in alignmentwith the exposed portion of the pressuresensitive adhesive tape 34.

The sheet feeding belt 20 is made of a high-friction material such asflexible polyurethane and it is supported with its lower run directlyabove and normally spaced from the sole 70 of the shoe 22 generallyparallel to the bottom wall 14 of the tray 12 and the inclined sheetfeeding wall 32. The belt 20 extends around and is supported by an idlerroller 76 and a continuously driven roller 77. The idler roller 76 issupported by a bracket 79 further over the edge of the bottom wall 14 ofthe tray 12 than the shoe 22 to position a portion of the sheetfeedingbelt 20 over the stack of sheets 26. The driven roller 77 is secured toa shaft 81 that is rotatably supported by the stationary supportcastings 25 and 27 and that carries a pulley 83 which is suitably drivenfrom a motor (not shown) through the driven belt 60. A sheet-feedingsponge roller 85 has a segment secured to the driven shaft 81 on eachside of the sheetfeeding belt 20 and its peripheral surface contacts theinclined sheet-feeding wall 32 to frictionally drive a sheet down theinclined feeding wall 32. A switch 86 has a leaf spring extending intothe path of a sheet fed by the sponge roller 85 to deactivate thesolenoid 61 and thereby the driving clutch 57 when the driving disk 52completes a revolution. The solenoid 61 is, therefore, deactivated whenthe leading edge of a sheet 26 reaches the sponge roller 85 andreactivated when the trailing edge of a sheet leaves the sponge rollerto provide rapid sheet feeding.

At the end of the hexagonal shoe shaft 66, adjacent the stationarysupport casting 25, is a crank arm or link 87, which extendsperpendicularly from the hexagonal shaft 66. A second longer link 88 ispivotally connected to the free end of the short link 87 and extendsupward alongside the bottom wall 14 of the tray 12 to the driving disk52 where it is rotatably con nected off center on a stud 90. The links87 and 88 and the driving disk 52 provide the desired movement of theshoe 22 as will be hereinafter described.

The movement of the tape head 18 controlled by its fourbar linkage andthe movement of the shoe 22 controlled by links 87 and 88 are timed orcoordinated by the driving disk 52 which is in turn controlled by thesolenoid 61 through the clutch 57. Upon each revolution of the drivingdisk 52 a single sheet 26 is fed off the stack of sheets 26 on thebottom wall 14 of the tray 12 over the abutment wall 16 and down theinclined sheet-feeding wall 32. The movement of the tap head 18 by itsfour-bar linkage and the shoe by its linkage upon one counterclockwise(as viewed in FIG. revolution of the driving disk 52 is diagrammaticallyillustrated in FIGS. 2 through 4.

FIG. 2 illustrates the tape head 18 and the shoe 22 in their first ornormal rest position. As the driving disk 52 starts its revolution, shoe22 is rotated out of contact with the stack of sheets 26 through theaperture 68 in the abutment wall 16 to the position illustrated in FIG.3. At the same time the tape head 18 is first rotated through a shortclockwise are (as viewed in FIGS. 2 through 4). The bottom wall 14 ofthe tray 12 which is urged upward by the compression spring 28 thenpresses the uppermost sheet in the stack against the rear portion of thetape head housing 36 without contacting the exposed portion of thepressure-sensitive adhesive tape 34. The tape head 18 is then rotatedcounterclockwise to its second position illustrated in FIG. 3 therebycontacting the exposed portion of the tape 34 against the uppemiostsheet in the stack and rotating it across the sheet 26 to establish firmadhesive connection. in moving to its third position illustrated in FIG.4, the tape head 18 moves slightly back relative to the tray to move theleading edge of the uppermost sheet 26 from the abutment wall 16 of thetray 12. 1t then rotates clockwise to lift the leading edge of theuppermost sheet above the abutment wall 16 and into contact with thesheet-feeding belt 20. At the same time the shoe 22 is pivoted clockwiseto position its toe 72 over the stack of sheets beneath the lifted sheetwith the sole 70 of the shoe 22 contacting the sheet to place the liftededge of the sheet 26 in frictional engagement with the sheet-feedingbelt 20 which then peels the lifted sheet from the adhesive tape 34 ofthe tape head 18 and drives the sheet under the sponge roller 85. As theshoe makes this movement its toe 72 depresses the bottom wall 14 of thetray 12 to separate the stack of sheets from the tape head 18 andthereby to relieve the pressure between the already lifted sheet and thehousing 36 of the tape head 18. As the driving disk 52 completes itsrevolution the tape head 18 and the shoe 22 are moved from their thirdposition illustrated in FIG. 4 back to their first or rest positionillustrated in FIG. 2.

A lever 94 is also provided to lift the tape head 18 farther from thebottom wall 14 of the tray 12 than in its normal position when it isdesired to manually feed sheets. Lever 94 is supported on a pin 95 forrotation from a rear stop 96 in the automatic feed position to a frontstop 97 against which it is rotated when it is desired to manually feedsheets. The lever 94 extends out of the cabinet 11 as illustrated inFIG. 1 to provide ease of switching from automatic to manual feeding.The lever 94 is connected to the tape head 18 by a short cam link 99,and adjustable floating link 100, and a generally horizontal link 101.The horizontal link 101 is pivotably on a pin 102 extending from thestationary support casting 25 and it supports the normally stationaryend of the curved link 42 which forms a part of the four-bar linkage formoving the tape head 18. The curved link 42 thus provides lifting of thetape head 18 when the lever 94 is rotated from the rear stop 96 to thefront stop 97.

In use, a stack of sheets 26 is placed on the bottom wall 14 of thestray 12 and pushed against the abutment wall 16 under the toe 72 of theshoe 22. When it is desired to feed sheets from the stack the solenoid61 is activated to retract its plunger arm 62 thereby permitting theclutch 57 to lock the pulley 59 to the driving shaft 55 to rotate thedriving disk 52. As the driving disk starts its rotation the shoe 22moves away from the stack of sheets and the tape head 18 contacts theuppermost sheet 26 and lifts its end above the abutment wall 16 and intocontact with the sheet-feeding belt 20. As the sheet is being lifted theshoe 22 is pivoted back over the bottom wall 14 of the tray and the toe72 of the shoe 22 depresses the bottom wall 14 by contacting the stackof sheets thereby aiding in separating the lifted sheet from theremaining stack of sheets. At the same time the sole 70 of the shoe 22contacts the sheetfeeding belt 20 and the lifted end of the uppermostsheet thereby causing the sheet to be driven by the belt 20 over thesmooth surface of its sole 70. The sheet is then driven between thesponge roll and the inclined sheet-feeding wall 32 to drive it down theinclined sheet-feeding wall 32 as desired. As the leading edge of thesheet crosses under the sponge roller 85 it closes switch 86 therebydeactivating the solenoid 61 to move the plunger arm 62 so that theclutch 57 is disengaged when the driving disk 52 completes itsrevolution. The tape head 18 and the shoe 22 then return to their normalrest position with the sole 70 of the shoe 22 spaced from thesheetfeeding belt 20. When the trailing edge of the lifted sheet passesover the switch 86 the solenoid 61 is activated, the clutch 57 isengaged and a second uppermost sheet is fed in the same manner as thefirst sheet.

Having thus described the present invention, what is claimed is:

1. An automatic sheet separator and feeder comprising:

support means including a bottom wall for supporting a stack of sheetsand an abutment member over which it is desired to feed sheets seriatim.

sheet-lifting means positioned adjacent said support means abutmentmember and movable toward and away from a said bottom wall and thus asaid stack of sheets for engaging and lifting the end of the uppermostsheet in a said stack above said abutment member,

driven means extending over said support means abutment member tocontact a said end of a said uppermost sheet lifted by said liftingmeans, and

shoe means positioned below said driven means and having a toe to extendover and contact a said stack of sheets for separating a said lifteduppermost sheet from a said stack of sheets and a sole engageable withsaid driven means simultaneously with said toe contacting a said stackof sheets to press a said lifted end of a said uppermost sheet againstsaid driven means to cause said driven means to drive a said uppermostsheet across said sole.

2. An automatic sheet separator and feeder as recited in claim 1including timing means for moving said sheet-lifting means and said shoemeans to position said sole of said shoe means in engagement with saiddriven means as said sheet-lifting means lifts a said end of a saiduppermost sheet into contact with said driven means.

3. An automatic sheet separator and feeder as recited in claim 1including linkage means for supporting said shoe means for pivotalmovement from a first position wherein said toe overlies a said stack ofsheets and engages the uppermost sheet thereof, to a second positionspaced from a said stack, to a third position with said toe separating asaid lifted uppermost sheet from a said stack of sheets and with saidsole placing a said lifted end of a said uppermost sheet in drivingengagement with said driven means, and back to said first position.

4. An automatic sheet separator and feeder as recited in claim 3including means for supporting said bottom wall of said support meansfor pivotal movement about an axis parallel to and spaced from saidabutment member and resilient means fur urging said bottom wall towardcontact with said sheet-lifting means, and wherein said toe of said shoemeans contacts a said uppermost sheet on said bottom wall in said firstand third positions thereof to retain a said uppermost sheet out ofcontact with said lifting means 5. An automatic sheet separator andfeeder as recited in claim 4 wherein said sheet-lifting means comprisesa length of pressure-sensitive adhesive tape and tape head means forsupporting said length of tape with a portion thereof supported tocontact and adhere to a said uppermost sheet for lifting the end of saiduppermost sheet in a said stack above said abutment member.

6. An automatic sheet separator and feeder as recited in claim 5 whereinsaid tape head means includes wall means for contacting a said uppermostsheet on said bottom support wall as said shoe means is moved from saidfirst position to said second position, and said separator and feederincluding linkage means for pivotally supporting said tape head meansand timing means for moving said sheet-lifting means and said shoe meansto contact said supported portion of said tape against a said uppermostsheet as said shoe means is advanced toward said second position and torotate said tape head to lift the end of a said uppermost sheet intocontact with said driven means as said shoe means reaches said thirdposition whereby said shoe means frictionally engages a said liftedsheet with said driven means to peel a said sheet from said supportedtape portion to feed a said sheet from a said stack.

1. An automatic sheet separator and feeder comprising: support meansincluding a bottom wall for supporting a stack of sheets and an abutmentmember over which it is desired to feed sheets seriatim, sheet-liftingmeans positioned adjacent said support means abutment member and movabletoward and away from a said bottom wall and thus a said stack of sheetsfor engaging and lifting the end of the uppermost sheet in a said stackabove said abutment member, driven means extending over said supportmeans abutment member to contact a said end of a said uppermost sheetlifted by said lifting means, and shoe means positioned below saiddriven means and having a toe to extend over and contact a said stack ofsheets for separating a said lifted uppermost sheet from a said stack ofsheets and a sole engageable with said driven means simultaneously withsaid toe contacting a said stack of sheets to press a said lifted end ofa said uppermost sheet against said driven means to cause said drivenmeans to drive a said uppermost sheet across said sole.
 2. An automaticsheet separator and feeder as recited in claim 1 including timing meansfor moving said sheet-lifting means and said shoe means to position saidsole of said shoe means in engagement with said driven means as saidsheet-lifting means lifts a said end of a said uppermost sheet intocontact with said driven means.
 3. An automatic sheet separator andfeeder as recited in claim 1 including linkage means for supporting saidshoe means for pivotal movement from a first position wherein said toeoverlies a said stack of sheets and engages the uppermost sheet thereof,to a second position spaced from a said stack, to a third position withsaid toe separating a said lifted uppermost sheet from a said stack ofsheets and with said sole placing a said lifted end of a said uppermostsheet in driving engagement with said driven means, and back to saidfirst position.
 4. An automatic sheet separator and feeder as recited inclaim 3 including means for supporting said bottom wall of said supportmeans for pivotal movement about an axis parallel to and spaced fromsaid abutment member and resilient means for urging said bottom walltoward contact with said sheet-lifting means, and wherein said toe ofsaid shoe means contacts a said uppermost sheet on said bottom wall insaid first and third positions thereof to retain a said uppermost sheetout of contact with said lifting means.
 5. An automatic sheet separatorand feeder as recited in claim 4 wherein said sheet-lifting meanscomprises a length of pressure-sensitive adhesive tape and tape headmeans for supporting said length of tape with a portion thereofsupported to contact and adhere to a said uppermost sheet for liftingthe end of said uppermost sheet in a said stack above said abutmentmember.
 6. An automatic sheet separator and feeder as recited in claim 5wherein said tape head means includes wall means for contacting a saiduppermost sheet on said bottom support wall as said shoe means is movedfrom said first position to said second position, and said separator andfeeder including linkage means for pivotally supporting said tape headmeans and timing means for moving said sheet-lifting means and said shoemeans to contact said supported portion of said tape against a saiduppermost sheet as said shoe means is advanced toward said secondposition and to rotate said tape head to lift the end of a saiduppermost sheet into contact with said driven means as said shoe meansreaches said third position whereby said shoe means frictionally engagesa said lifted sheet with said driven means to peel a said sheet fromsaid supported tape portion to feed a said sheet from a said stack.